Recent studies of undocumented labor migrants from rural Mexico have provided us with a general profile of such workers. They are mainly single males who are unskilled and poor. This profile applies generally to much of the rural Mexican populations, yet migration is clearly a selective process, inasmuch as most migrants come from only five Mexican States, and from specific zones within them. Because the profile is based on interviews of individuals apprehended in this country, it does not provide an understanding of the socio-economic context in the home community which propels individuals into the migration stream. The goal of the research is to test a set of hypotheses about aspects of such migration: choice of destination (U.S. vs. locations within Mexico); choice of U.S. destination (rural vs. urban); and length of stay in the United States. The unit of analysis is households which are seen as exercising the migration option as one means of adapting to changes within the regional economy. Data will be collected in selected households in the two contrasting communities in Michoacan, Mexico. The information provided by the research is expected to add to our understanding of the causes of selective migration. Such information is needed in order to assess more accurately the impact of temporary labor migration on social and health services in the United States.